Bow straightening apparatus



F. J. STEVENS 2,137,252 BOW STRAIGHTENING APPARATUS Nov. 22, 1938! 4 2 Sheets-Sheet 1 Filed- Au "12.v 1936 l'wpenfior fit (22% Siwezzs- Patented Nov. 22, 1938 UMT D STATES PATiENT-fi Fist now STRAIGHTENING -A Frank J. Stevens, Providence, R. III, assignor t o Cranston Print Works Company, Cranston, R. 1., a. corporation of lthode'lsland" Application August 12, 1936, Sicrial Napalm v 8 Claims. (o1;"26;52f)f -This inventionrelates tobow straightening apparatus. Itiis'herein particularly shownv and described in its application to a tentering machine but this is merely illustrative because it may be used with any continuously moving strip of cloth. 1 i

In the weaving of fabric the threads of the woof, called filling threads, are laid or woven straight across the warp and it is important that they remain so throughout the subsequent processing of the goods. It is readily-appreciated that if these cross threads are laid straight to form a desired pattern and" later become curved, called in the art bowing, serious and damaging deformity of the pattern results. Likewise with plain cloth which is to be printed with some design, if the filling threads are not straight across when the piece is printed it is well-nigh ruinous to the design if straightening go of the bowing is later" attempted. And even where the cloth is not woven or printed with any figurative design, being simply plain goods, itis nevertheless highly desirable to have no bowing not only as a matter of appearance but because when the goods are finally cut to a pattern bowing leads to unexpected distortion of ther cloth when it is eventually made up into a garment;

It is an object of this invention-to provide means to straighten the bowing of the filling threads. Cloth is Woven into long strips or pieces which, during the subsequent processing, are temporarily stitched together so that the fabric may continue to be fed as a strip indefinitely. Generally speaking whenever such a continuous strip is being fed it is possible for the bowing to occur, but it almost invariably occurs whilethe cloth is passing through a tentering'machine. Accordingly the present invention may be employed particularly with a tentering machine, and m such use is herein disclosed as the bestmode in which I have contemplated applying the principles of my invention. As previously noted, this showing is to be taken as merely illustrative for it is intended that the patent shall 'coverby suitable expression in the appended claims whatever features of patentablenovelty exist in the invention as a whole.

Figure 1 is a plan view of several sections of a strip of fabric, showing somewhat diagrammatically how the bowing may occur;

Figure 2 is a side elevation of the head or delivery end of tentering machine to which my device has been applied;

Figure 3 is a similar elevation of the same, 55 partly in section as on line 3-3 of Figure 6;

Figure; -4 -is' a side-elevation, as in section on line 4--4 of Figure 6, through the novel feeding rolls; H

Figure. 5 is a plan view; and v Figure 6 is-af-ront elevation taken as on line 6-6 of Figure 2.

Y Referring nowmore particularly to the drawings andespecia'llyto Figure 1, it is highly desirablefor thetwoverr fabric to remain as indicated at ii-with; the-woofer filling threads B straight acrossthe warp threads C. Unfortunately this desired conditionds-seldom realized and more often than not the;woof .threads become curved as shown at Bland; atB2. As. previously stated the presentinvention is,directed to the straightening. of suchbowing, Whether the filling threads becurvcd asatBl orreversely curved as at B2.

A tentering machine affords a most desirable place in theprocessing of cloth for the employment of my invention. In a tenter the cloth is stretched sidewise promptly after entering the machinenandgthereafter travels a considerable distance with theselvage engaged by the traveling clipsof-the machine. .The drawings show the head or delivery end 101 a tenter with my improved' bow eliminatingmeans applied thereto. The head end ,comp-rises, side frame members I andlcarrying a-main drive shaft 3 which may be driven from any suitable source of power. Splined to this shaft, and movable therealong, ar ebeveled pinions land 51. Each pinion meshes with, a beveled g'earfi, I, attachedto the lower end of a vertical shaft 8, 9, to the upper end of which is secured a sprocket. gear in; II. Each sprocket gear-drives an endless chain l2, l3 indicatedby the dotand-dash lines in Figure 5.

This chain comprises aseries of clips I4, shown in Figure 6, those of one chain gripping one side. of the cloth strip A while the. clips of the other chain grip the other side, of the strip. The chains extend for a considerable longitudinal distance, being, guided by chainrails l6, I! from the cloth receiving end to the. delivery or head endof the tenter. Asa chain reaches its sprocket gear the clips are engaged by an opening flange l8, l9 and caused to open, therebypermitting the cloth to tco n tinue forward asthe chain reverses its direction of travel. The stretched cloth passes over .abar 20 to a winder, (not shown) where it is wound on itself into a roll.

All of the apparatus thus far described is old inthe art and-is merely representative of any tenter, herein. disclosed as indicating broadly anymeans for feeding the .edges of a piece of clcth Thenovelapparatus will now be described,

by means of which apparatus any bowing of the filling threads may be straightened and the cloth delivered to the winder with these threads positioned straight across the strip.

Secured to the side frames and 2 are standards 2| 22 carrying an axle rod 23 to which is secured arms 25, 26 between which is rotatably supported a roll 21. These arms are so-positioned on the rod 23 that the center of the roll 21 will be substantially over the center line of the fabric piece A, whose edges are indicated by dotted lines a, a in Figure 5. Beneath the cloth is another roll 28 rotatably supported by arms 29, 30 on standards 3|, 32. The shaft 33 of this lower roll 28 carries a sprocket gear 34 which is connected by chain 35 to a variable speed control device 36 of any suitable design which may, for example, be driven by another chain 31 running between gear 38 and a sprocket gear 39 on the main drive shaft 3. Obviously the speed of chain 35, gear 34 and roll 28 may be difierent from that of gear 38 as determined by the setting of the variable speed controller 36. The hand-wheel 40 is representative of any suitable means for determining the setting of the device 36 and the speed of roll 28.

At one end of the rod 23 is securedan arm 4| which is connected by an extended link 42 with a chain or cable 43 running through a housing 44 and around a guide wheel 45 to a vertical shaft 46. The latter is provided with external threads which are engaged by a hand-wheel nut 41 at the upper end of a suitable support 48. By turning this hand-Wheel, shaft 46 may be raised or lowered and, by means of chain 43 and link- 42, the arm 4| may be turned. This will cause the axle rod 23 and arms 25, 26 to likewise turn and either press roll 21 toward roll 28 or move the rolls apart. Secured to arm 4| is a spring member 49 so arranged as to constantly urge arm 4| upward, thus imposing a tension on the chain 43.

While it is to be understood that both roll 21 and 28 may be cylindrical rolls, I prefer that one of them shall be non-cylindrical as shown. As illustrated, roll 21 is not a true cylinder but has its greatest diameter at the middle and its smallest diameters at the ends. Between these extremes of diameter the variation may be gradual and uniform in which case the longitudinal elements of the roll surface are straight lines'from the middle to each end. Or the surface may be shaped so that the elements are curved lines, either uniformly so or variably so with the curvature increasing toward the ends. As here shown, the upper roll 21 has the longitudinal elements of its surface, as straight lines while the lower roll 28 is truly cylindrical, but these relations might be reversed with the upper roll cylindrical and the lower roll of varying diameter.

It is also preferable that one of the rolls 21, 28 have a surface which is somewhat yieldable so that as the rolls are moved closer together the extent of engagement of the cloth will be varied. As here shown the upper roll21, represented as being made of a suitable rubber composition, but it might be provided merely with a surface covering of such. material or other material of yieldable nature.

As the strip passes the bar 20 and becomes visible to the operator standing beyond the winder (not shown) in the neighborhood of the hand-wheel 41, he can readily determine whether or not any bowing is present in the cloth. If he finds that the cross threads are curved as at Bl in Figure 1, and the cloth is moving in the direction of the arrows, he turns hand-wheel 41 to raise shaft 48 and thereby depress the arms 4|, 25 and 26. This forces the upper roll 21 toward the lower roll 28 and where the noncylindrical surface of the upper roll firmly presses the cloth A which is between the rolls against the lower roll, that portion of the cloth will assume the speed of travel of the surface of roll 28.

With the filling threads bowed as at Bl in Figure 1, the variable speed device will be set so that the roll 28 is traveling at a greater speed than the cloth. In consequence, as the cloth is gripped by the rolls the portion so gripped will be speeded up and travel forward faster than the edges of the strip. Because of the varying diameter of the upper roll, the greatest pressure is exerted on the piece at its middle where the diameter of the upper roll is largest and less pressure will be exerted progressively towards the ends of the roll. This variation in pressure results in variation cloth by the rolls so that the middle portion 'of the piece is speeded up to the greatest extent while toward the ends of the rolls as the pressure between them lessens the cloth is permitted gradually to slip so that its speed approaches the speed of the edges. This leads to a complete straightening of the bowing and restores the WOOf threads straight across the warp.

If the bowing is in the reverse direction, as at B2 in Figure 1, the speed of the roll 28 will be adjusted to less than that of the cloth and as a result the middle portion of the strip will be most retarded with less retardation toward the ends of the rolls. Again the bowing will be eliminated.

It is evident that if the bowing is not too great, the necessary variation in speed to be imparted by the rolls can be controlled almost entirely by the hand-wheel 41, but if the bowing should be unusually large, then it is desirable to change the speed of the rolls by means of the variable speed device 36. Such changes are readily-made by the operator while the strip is continuing to travel and as a result the cloth is presented to the winder and wound up thereon with the bowing eliminated.

While I have shown the upper roll 21 as a pressure roll it is to be understood that this roll might also be positively driven, in which event the lower roll could be a pressure roll or driven as shown. Also, the lower roll might be arranged to be moved toward or from the upper roll, but I prefer the arrangement shown.

I claim:

1. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously engaging the piece intermediate of its edges and capable of positively moving said piece intermediate of its edges at a speed different from that of the said edges; the said piece being moved in its own plane by the said engaging means.

2. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously engaging the piece intermediate of its edges and capable of positively moving said piece intermediate of its edges at a speed different from that of the said edges; the said piece being moved in its own plane by the said engaging means so as to impart the greatest difference in speed to in the speed imparted to the.

that portion of the piece where the bowing is greatest and to impart less difference in speed from said portion toward the edges of the piece.

3. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the last said means comprising a pair of rolls engaging the piece intermediate of its said edges.

4. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the last said means comprising a cylindrical roll and a non-cylindrical roll constructed and arranged to engage the piece intermediate of its said edges.

5. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the last said means comprising a cylindrical roll and a non-cylindrical roll constructed and arranged to engage the piece intermediate of its said edges; one of said rolls having a yieldable surface and there being means to control the relation of said rolls to one another to vary the extent of engagement of the piece between them.

6. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and caof cloth comprising, in

pable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the

last said means including a cylindrical roll and a non-cylindrical roll having its greatest diameter substantially at the center line of said piece; one of said rolls having a yieldable surface and there being means for moving said rolls relatively to one another to engage the piece between them.

'7. Apparatus for eliminating bowing in a piece of cloth comprising, in combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the lastsaid means comprising a'pair of rolls engaging the piece between them; and means for changing the speed of said rolls to vary the relative speed of said edges and the piece intermediate of its edges.

8. Apparatus for eliminating bowing in a piece combination, feeding means engaging the edges of said piece and capable of positively moving each edge at a predetermined speed and means for simultaneously feeding the piece intermediate of its edges at a speed different from that of the said edges; the last said means comprising a cylindrical roll and a non-cylindrical roll constructed and arranged to engage the piece intermediate of its said edges; the non-cylindrical roll being made of yieldable material; and means for moving said non-cylindrical roll toward or from the other roll to vary the extent of their engagement with the piece.

' FRANK J. STEVENS. 

